History

The Martian Schism originated in a climate of discontent; relations between various Magi were in a condition of tension, with outbreaks of violence and espionage leading to even the Titan Legions being suspected of secretly taking sides in potential hostilities[1a]. For years, factions on Mars had bitterly argued over the nature of the Omnissiah, with many believing the Emperor to be its avatar. However a large faction led by Fabricator-GeneralKelbor-Hal maintained the Emperor a false idol and the manifestation of the Omnissiah had yet to arrive. More importantly, Kelbor-Hal harbored great resentment to Emperor for his conversion of Mars into an arms factory for the Great Crusade and his ban on certain types of technological research (such as artificial intelligence).[1] Into this situation came Regulus, Mechanicum representative to WarmasterHorus.[1e] By this point in history, the Warmaster had already settled upon his course of rebellion and had secretly gained the tentative support of the Mechanicum through Regulus and his connection to Kelbor-Hal, the Fabricator-General. Regulus' visit to Mars at this juncture was to demonstrate the commitment of Horus to the alliance with the Mechanicum and the advantages to siding with the Warmaster against Imperial rule. As a result of the information provided by Horus and carried by Regulus, Kelbor-Hal was able to open a long-sequestered area of Mars known as the Vaults of Moravec.[1b]

The Vaults of Moravec were a repository of forbidden knowledge, ordered sealed by the Emperor himself. It soon became clear that the information and industry stored within the Vaults were corrupted by the influence of Chaos. With the opening of the Vaults, this corruption spread across Mars in a peculiarly literal way; as scrapcode. This viral information infection managed to penetrate systems and facilities all across the Martian industrial landscape, causing literal chaos wherever it struck. As a result of the scrapcode infestation, communication across and off-planet was severely disrupted and many essential industries sabotaged. A period of general confusion followed, which the Fabricator-General and his allies used to marshal their forces, intent on making sure the whole of Mars was firmly under their rule. This proved to be somewhat more troublesome than they had anticipated.Several areas of Mars remained relatively uninfected by scrapcode, insulated against the assault by their early adoption of a new, far more secure information network; the noosphere. Three of these areas were the Forges of Koriel Zeth, Ipluvien Maximal, and Fabricator-LocumKane, who would go on to become the leaders of those resisting sublimation into Kelbor-Hal's new Dark Mechanicum.[1e]

While the opening shots had already been fired when the Kaban Machine of Lukas Chrom destroyed a reactor complex belonging to loyalist Adept Ipluvien Maximal, it still took a short while before open civil war began. Requiring at least a pretense to march to war, Kelbor-Hal and his allies attempted to provoke those unwilling to join them, employing various acts of sabotage, assassination and outright aggression - as when the Dark Mechanicum-aligned Legio Mortis attempted to goad Legio Tempestus into opening fire first by entering Tempestus territory and refusing to answer hails.[1c]

Eventually the pretense Kelbor-Hal required was given to him by Koriel Zeth, Mistress of the Magma City, when she declared non-belief in the Machine God (while this was her belief, she was still loyal to Terra). The Dark Mechanicum went to war against the Magma City, bringing war to Mars as those pledged to Kelbor-Hal and Horus attacked those pledged to Terra and the Emperor. The Magna Legion assaulted the Noachis region and reduced its libraries and forges to slag. North in the Arabian region, High Magos Ahotep's forge-city in the Cassini crater was struck by a hundred nuclear missiles launched from traitor silos. Along the Lunae Palus and Arcadia regions, the Death Stalkers assaulted the fortress of Maxen Vledig's Deathbolts. Caught by surprise, the Deathbolts lost 19 Titans in the first hour and withdrew to Mare Boreum where they were quickly besieged. At the Athabasca Valles the Legio Ignatum and Burning Stars fought to a stalemate in bloody close-ranged combat. Kelbor-Hal himself soon unleashed his twisted Skitarii and Combat Servitors on the Forges of Ipluvien Maximal. Maximal was able to repel the first wave of attackers, but within hours he was totally besieged by Ordinatus engines. At the Herschel impact basin of the Mare Tyrrhenum, 900,000 Skitarii and Protectors clashed in a bloody melee that continued until nearly all were dead.[1]

The single greatest loss of life of the war took place at the Ismenius Lacus forge-city after Dark Mechanicum forces unleashed Virus Bombs, killing 14 million within minutes. The apocalyptic conflict was not limited to the surface of Mars, and high above in the planet's orbital shipyards traitor ships exchanged fire with their loyalist counterparts after forcing Battlefleet Solar to withdraw. The Mechanicum Glorian was destroyed by Dark Mechanicum Frigates and crashed into the Basilica of the Blessed Algorithm on Mars itself. The crash annihilated millions of square kilometers and killed billions across the planet.[1]

While conflict erupted all over the red planet, the Magma City soon became the focal point for the resistance, with both Legio Tempestus and the Knights of Taranis coming to Zeth's aid. Holding against the chaotic power of the Dark Mechanicum was a difficult business and soon not only Zeth's forge, but those of Maximal and even Kane found themselves becoming effectively surrounded by enemies and besieged. A vicious battle erupted at Magma City, led by the Legio Mortis and the Imperator TitanAquila Ignis. However the Legio attack on Magma City was blunted when lava overran the traitor ranks, and most of the Titans of the Legio Mortis (including the Aquila Ignis) were destroyed by the Legio Tempestus. But despite the victory at Magma City, the situation remained dire for the outnumbered and outgunned loyalist forces across the planet.[1e]

Twin beacons of hope for those still loyal to the Terran-Martian alliance appeared when two Imperial assault forces made up of Imperial Fists Astartes and Imperial Army formations drawn from the Solar levies under the commands of CaptainsSigismund and Camba-Diaz arrived on Mars[1d], touching down and intending to secure the two main forge-complexes which supplied Astartes arms and equipment, that of Kane and that of Lukas Chrom. Unfortunately for Camba-Diaz, Chrom, whose complex he was sent to secure, was one of the leading traitors, and a vicious battle between Imperial and Dark Mechanicum forces broke out in his forge complex as a result. Sigismund was more successful, being able to secure Kane's forge - Mondus Occulum - and even able to sally out and attempt to aid the Martian loyalists. All the while this was happening, Sigismund was making sure that as much arms, ammunition, armour, and material as possible was being sent back to Terra from Mondus Occulum.[1e]

However, despite the Imperial reinforcement, it soon became grimly clear that the Dark Mechanicum must be triumphant. Recognising the inevitable, Sigismund issued an evacuation order for all loyalist forces, taking with him as much and as many as he could when he and the Imperial forces finally left, including Fabricator-Locum Kane. The other leaders of the resistance, as well as that part of Legio Tempestus on Mars and nearly all of the Knights of Taranis, eventually died fighting the pernicious and relentless assaults of the Dark Mechanicum, leaving all of Mars effectively under the influence of Horus.[1e]

In the aftermath of the battle, Imperial forces from Terra blockaded the planet, leading to several attempts by the Traitors of Mars to breakout. The containment of Mars was overseen by Imperial Fists commander Efried.[3] However ultimately, Mars would not be reclaimed under after the Battle of Terra.[2]